Messages in this thread | | | Date | Thu, 29 Aug 2002 19:25:19 -0400 (EDT) | From | Mark Hahn <> | Subject | Re: Passing kernel parameters |
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> Unfortunately this is not working. dmesg for ide still shows the following: > ide: Assuming 33MHz system bus speed for PIO modes; override with > idebus=xx > > despite the fact that I've specified 'idebus=66' and the following lines note: > > VP_IDE: VIA vt82c596b (rev 12) IDE UDMA66 controller on pci00:07.1
note that it says *system* bus speed. that is, the clock fed to the IDE controller (usually the PCI clock, 33 MHz). this is NOT the transfer mode!
by lying to the driver that "idebus=66", all you accomplish is making your transfers half the speed they should be. the driver says "since the clock period is 15ns, and I want (say) udma33 (16b every 60ns), I'll tell the controler to do 16b every 4 clocks."
alas, the real period is 30ns, so you get 16b every 120ns. voila, udma16 ;(
summary: don't lie to the driver; the default is probably correct.
regards, mark hahn.
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